Human Physiology Exam Review

Flashcards based on Human Physiology lecture notes to help with exam preparation.

What functions are associated with the conducting zone of the respiratory system?

Humidifying, filtering, and warming air.

What is the primary muscle responsible for inspiration?

Diaphragm

What term defines the volume of air inhaled or exhaled during each respiratory cycle?

Tidal volume

What term defines the total volume of air that can be moved from the lungs from full inspiration to full expiration?

Forced vital capacity

What muscles are recruited during forced expiration?

Internal intercostals

What pressure changes occur during inspiration?

Increase in lung volume, decrease in alveolar pressure

Which brain respiratory control center speeds up the basic rhythm of breathing when activated?

Apneustic area

Where are peripheral chemoreceptors located?

Aortic arch

Which stimulus are central chemoreceptors more receptive to?

PCO2

In which blood vessel does diffusion principally occur?

Capillaries

How many iron molecules does myoglobin contain?

1

Which factor does NOT influence the oxyhaemoglobin dissociation curve?

Blood viscosity

What is the final site of oxygen binding in the muscle?

Cytochrome c oxidase

Which ion moves into the red blood cell as bicarbonate is released?

Chloride

Why is the blood oxygen content lower at high altitude?

Less oxygen and lower PO2

Which heart vessel pumps blood around the body?

Left ventricle

Which blood vessel transports oxygenated blood from the lungs to the heart?

Pulmonary vein

What is the name for heart muscle?

Myocardium

Which component of the cardiac muscle conduction system initiates the signaling for the heart to beat?

Sinoatrial node

What technique is used to measure the electrical activity of the heart?

Electrocardiogram

What does the P wave represent on an ECG?

Atrial depolarisation

What term describes the highest pressure within the vascular system generated during cardiac contraction?

Systolic blood pressure

Which parameter has the greatest influence on blood flow?

Blood vessel radius

Which variable does not increase during exercise?

Total peripheral resistance

In which body part does blood flow not decline during exercise?

Brain

What is the natural intrinsic rhythm of the heart?

100 bpm

Which molecule is not released by the smooth muscle of blood vessels to promote vasodilation?

Iron

The process by which water moves between compartments is known as what?

Osmosis

Which factor has least impact on determining daily water needs?

Sleep duration

Which electrolyte is most prevalent in the extracellular fluid?

Sodium

Which electrolyte is most prevalent in the intracellular fluid?

Potassium

Which hormones play an important role in body fluid balance?

Antidiuertic hormone and aldosterone are both important

Which option best describes the cardiovascular consequences of dehydration?

↓ end-diastolic volume, ↓ stroke volume, ↓ cardiac output

Which option best describes the cognitive consequences of dehydration?

↓ visual motor tracking, ↓ attention, ↓ reaction time

What causes hyponatremia?

Loss in sodium from the interstitial fluid and plasma

What is the optimal beverage to promote rehydration following endurance exercise?

Same volume as volume of sweat lost during exercise + high sodium

Hypothermia occurs when the body core temperature falls below what?

35°C

Which hormone is not responsible for increasing metabolic rate?

Insulin

Why does muscle temperature rise during exercise?

Most of the chemical energy released from ATP breakdown is converted to heat

What is the main form of heat loss at rest?

Radiation

In which condition would sweat evaporation be the lowest?

High temperature, high humidity, wind-free

Which option best describes the physiological processes that occur as body temperature falls at rest?

Thermoreceptors are activated, hypothalamus promotes shivering and signals for lower skin blood flow, body temperature rises

What happens to marathon and repeated-sprint performance in hot environments?

Marathon performance is impaired, repeated-sprint performance is impaired

What happens to sweating rate in the heat after heat acclimation?

Increased sweat rate and sweat is more dilute

Which factor is likely to limit oxygen delivery during maximal exercise?

Muscle pH

Which of the following statements is false?

maximum oxygen uptake is always higher in men than women

The age related decline in maximum oxygen uptake is related to

loss of mitochondria

While both the nervous and endocrine systems are critical for communication and coordination among body systems, the endocrine system responds more?

slowly but has longer-lasting effects

Cyclic AMP is formed when a hormone binds with a receptor and interacts with the enzyme

adenylate cyclase

Which of the following would decrease the sensitivity of muscle to insulin?

downregulation of insulin receptors

Nonsteroid hormones are characteristically

amino acid/protein based

A key characteristic of prostaglandins is that they

exert their effects locally

Which of the following pairs of hormones typically act in opposition?

insulin, glucagon

The anterior pituitary is controlled by

hypothalamic hormones

Which group of hormones exerts metabolic and cardiovascular effects during exercise?

catecholamines

Aldosterone release leads to

Na+ retention followed by water retention

Erythropoietin release is the primary stimulus for

red blood cell production

Ca2+ ions are stored in the

sarcoplasmic reticulum

Thick filaments are primarily made of which protein?

myosin

Which protein shields the myosin-binding site, preventing contraction from happening at rest?

tropomyosin

The process of plasmalemma depolarization involves which ion?

Na+

Why is it necessary to have an action potential to initiate muscle contraction?

The SR will only release Ca2+ if it has been electrically stimulated.

Which is the correct order of events in a contraction?

T-tubule action potential, Ca2+ released, cross-bridging, Ca2+ gathered in

ATP is required for

both muscle contraction and muscle relaxation

Fast twitch fibres exhibit the following characteristics except:

low myosin ATPase activity

Which of these consists of the basic repeating unit between two Z lines and makes up the functional unit of the skeletal muscle?

sarcomere

During contraction of a skeletal muscle fibre

the I band shortens

Which ion transporter is engaged at rest to maintain resting membrane potential?

Na+-K+-ATPase pump

If membrane potential changes from -40 mV to -35 mV, this is an example of

depolarization

Motor units differ according to their physiological and mechanical properties which of the following is not one of these characteristics?

stretch sensitivity

Which of the following nervous systems subdivides into sympathetic and parasympathetic components?

autonomic

The four different nerve fibre groups exist based on size include all of the following except:

omega

A sustained contraction of skeletal muscle due to a succession of stimuli with no time between stimuli for relaxation is called

tetanus

Which neurotransmitter binds to receptors on the motor end plate of a neuromuscular junction?

acetylcholine

During which state can a neuron only be stimulated by a stronger-than-normal stimulus?

the relative refractory period

The fastest impulses travel on axons that are

myelinated and large

An afferent neuron

sends impulses from the body to the brain

Which of the following is not involved in appetite regulation?

growth hormone

All except one of the following are involved in regulation of energy balance:

thymus

Which of the following is not an effect of insulin

increased glycogen breakdown

Which of the following statements is false?

when an impulse reaches the neuromuscular junction only some of the muscle fibres in the motor unit will respond

Which of the following indicates central fatigue?

decreased voluntary activation

Which of the following statements is false?

Central fatigue may be related to efferent feedback from the exercising muscle

The process of muscle contraction involves which ion?

Ca2+

Which part of the brain is primarily responsible for thermoregulation?

Hypothalamus

Sweating primarily helps the body to:

Lose heat

Vasoconstriction in cold environments helps to:

Conserve body heat

Thermoreceptors in the skin send signals to:

Hypothalamus

Which hormone contributes to increased metabolism and heat production?

Thyroxine

Pyrogens affect the hypothalamus by:

Causing fever

Which structure initiates shivering?

Posterior hypothalamus

Brown adipose tissue is important in thermogenesis due to:

Uncoupling protein-1

Heat is primarily lost from the body via:

Radiation

Which hormone regulates water retention in the kidneys?

ADH (Antidiuretic Hormone)

The majority of body water is found in which compartment?

Intracellular fluid

A key sign of dehydration is:

Dark urine

The thirst center is located in the:

Hypothalamus

Which electrolyte is most abundant in extracellular fluid?

Sodium

Which organ plays the largest role in regulating water balance?

Kidneys

Water intoxication can lead to:

Hyponatremia